Adjustable control mechanism for movably mounted blade of snow-plough

ABSTRACT

IN A SNOW-PLOUGH WITH A BLADE WHICH IS SWINGABLY ARRANGED ON A MOVABLE SUPPORTING MEMBER CONTROLLED BY A LIFTING DEVICE ON A CARRIER VEHICLE, THE SUPPORTING MEMBER IS PROVIDED WITH A VERTICALLY ADJUSTABLE STOP SKID WHICH PREVENTS THE BLADE FROM APPROACHING THE ROAD SURFACE OVER A PREDETERMINED DISTANCE, THUS PREVENTING THE BLADE FROM BEING BLOCKED WHEN ENCOUNTERING AN OBSTACLE.

United States Patent Inventor Walter in St. Blasien Black Forest, Germany Appl. No. 795,106 Filed Jan. 29, I969 Patent June 28. 1911 Assignee Alfred Schmidt 1ng.. Blasien/Schwarzwald,

Germ ny. Priority Feb. 29, 1968 Germany P 17 08 664.5

ADJUSTABLE CONTROL MECHANISM FOR MOVABLY MOUNTED BLADE 0F SNOW-PLOUGH 3 Claims, 3 Drawing Figs.

US. Cl 37/41, 172/801, 172/794 Int. Cl. E01h 5/06, 1302f 3/76 Field of Search 37/41, 42,

44-50; 172/801-807, 794 (Cursory) [56] References Cited UNITED STATES PATENTS 2,420,591 5/1947 Frame et a] 37/42 3,400,475 9/1968 Peitl .37/42 FOREIGN PATENTS 348,420 1960 Switzerland 37/41 Primary ExaminerRobert E. Pulfrey Assistant Examiner-Clifford D. Crowder Attorney-Nolte and Nolte ABSTRACT: In a snow-plough with a blade which is swingably arranged on a movable supporting member controlled by a lifting device on a carrier vehicle, the supporting member is provided with a vertically adjustable stop skid which prevents the blade from approaching the road surface over a predetermined distance, thus preventing the blade from being blocked when encountering an obstacle.

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ATTORNEYS 1 ADJUSTABLE CONTROL MECHANISM FOR MOVABLY MOUNTED BLADE F SNOW-PLOUGI-I The present invention relates generally to a protection mechanism for the blade of a snowplow.

In particular, the present invention relates to control member for a snowplough of the type which is attachable to a carrier vehicle and has a blade which is movably attached by means of at least one jointed arm and a' spring element to a vertically displaceable support member controlled by a lifting device arranged on a carrier vehicle.

Due to the movable arrangement of the blade on jointed arms and by the action of spring elements associated with the blade to force the latter in the direction toward the road surface, it is possible in the snowploughs of this type to insure that the blade can adjust itself to an uneven surface of the roadway and, when encountering'a small obstacle, such as a cover slab, for example, it will move upwardly to skid over the obstacle. The effective height of such displacement of the blade arranged in the above-described manner is defined by the design parameters of the swingable mechanism.

conventionally, the snowploughs are linked to the carrier vehicle by means of a lifting device which is adapted to force the blade against the surface of the road or to lift the same when normal transportation is required.

Such prior art arrangements, however, involve the danger that the movable support member to which the blade of the snowplow is attached by means of the jointed arms, may be as far displaced downwardly by the lifting device as the jointed arms are swung up into their upper limit position and, consequently, do not allow a further upward displacement of the removal share when the latter encounters an obstacle.

The object of the present invention is, therefore, to create a control mechanism for the snowplough which insures that the supporting member is lowered only so far in the direction toward the surface of the roadway that the blade can always be swung upwardly when encountering an obstacle.

According to the present invention, the above object is attained in that the blade support member is provided with a stop member which prevents the supporting member from approaching the surface of the roadway over a predetermined distance. 7

The stop member can be in the form of a simple support roller which is adjustably secured to and at a distance from the blade support member. Since the stop member in the course of a normal operation of the snowplough is out of contact with the road surface, it can be also made as a simple support skid. The support roller or skid is adjustably mounted in a holding jacket and its position with regard to the snowplough is set in the following manner:

The snowplough carrying vehicle is disposed on an even horizontal roadway, the blade is placed into the lowest position thereof with respect to the blade supporting member and the stop member is then vertically adjusted so as to be at a certain distance from the roadway. The distance usually corresponds to the height of the outstanding portion of the wearing strip which is attached to the lower edge of the blade. After the adjustment of the position of the stop member, the blade with a new, nonwomout wearing strip, can be swung up with regard to the blade supporting member only as high as the height of the outstanding wearing strip portion, so that the remaining swingable range thereof is unaffected, and the blade has always'the possibility to skid over the obstacles. This feature is particularly advantageous in the case when snow is cleared away from roadways having a surface which is undulated in the direction of travel.

, The invention is illustrated by way of example in the accompanying drawings in which:

FIG. 1 shows a side elevation of a conventional snowplough in a working position;

,FIG. 2 is the snowplough of FIG. 1 after encountering an obstacle; and

FIG. 3 is a snowplough having the control mechanism according to the present invention.

The prior art snowplough as shown in FIG. 1 comprises blade 1 which is swingably attached by means of pivotally mounted arms 2 and 3 to support member 4 which, in turn, is linked by swingable control arms 5 and 6 to a carrier vehicle 16.

Lifting device 7 is arranged in a known manner, between the lower control arm 6 and the vehicle to control the lifting of the supporting member 4. The supporting member is provided with rod 11 having nose 10 projecting between two limit stops 9a and 9b integral with the sidewall of blade 1. The blade is forced downwardly by means of spring 17 which acts to draw the nose 10 into abutment with upper limit stop 9a, thus defining the rest position of the blade with regard to supporting member 4, as shown in FIG. 1. Supporting member 4, control arms 5 and 6 and lifting device 7 constitute the control mechanism for the removal blade to control vertical position of the latter with regard to the carrier'vehicle and at the same time, to the surface of the roadway.

FIG. 2 illustrates the snowplough of FIG. 1 in a position resulting after the encounter of the lower edge of the blade with obstacle 8 on the road. Since the lower jointed arm at the rest position of the blade is inclined upwardly in the direction of the advance of the plough the inclination angle of the arm 2 will be increased when the blade is pressed against the obstacle, and the blade is accordingly swung up until the lower edge of nose l0 abuts against the lower limit stop 9b. However, if the blade supporting member is displaced towards the surface of the road to an extent such that the lifting device is in the lowest limit position thereof and the blade is swung up into its upper limit position (FIG. 2), there is no possibility for the arms to lift the blade any further in order to pass over an obstacle. The lifting action of arms 2 and 3 is, therefore, blocked due to the close approach of the blade supporting member to the roadway.

This shortcoming is overcome in the snowplough according to this invention, as shown in FIG. 3. The basic design of the snowplough is like that of FIGS. 1 and 2 and respective construction members thereof are designated by corresponding reference numerals. According to the present invention, the blade supporting member 4 is provided with a vertically ad'- justable stop member in the form of skid plate 12 integral with support column 13 which is adjustably mounted in holding collar 14 firmly connected with supporting member 4.

At the rest position of the blade, skid plate 12 is set to be at a certain distance from the road surface, preferably at a distance corresponding with the height of the outstanding portion of wearing strip 15 attached to the lower edge of blade I, as indicated in full lines in FIG. 3.

By dashed lines, there are illustrated in FIG. 3 individual parts of the snowplough in positions which result after the abutment of skid plate 12 on the roadway and, at the same time, when the blade has encountered obstacle 8. It is evident that skid plate 12 prevents arms 2 and 3 from being prematurely blocked due to the close approach of supporting member 4 towards the roadway and that blade 1 is always able to skid over the obstacle.

Iclaim:

1. In a snowplow, wherein a carrier vehicle has a blade support coupled to a front part of the vehicle for upward and downward swinging of the support, and biassed upwardly to space the support from the ground, the support having at least one scraper blade, linkage for said blade coupling the same to the support for upward and downward swinging of the blade, and limit means providing first and second limit positions of the blade, the first limit position being relatively low and forwardly spaced from the support, the second limit position being higher and closer to the support than said first limit position, and the blade being biassed toward the second limit position, for snow-ploughing but being swingable toward the first limit position to avoid an obstacle encountered on the ground, the improvement which comprises: an additional limit member, secured to said support and having at least a part thereof extending downwardly therefrom to a point below the the ground.

2. A snowplough according to claim 1, wherein said stop means is a plate adapted to skid on the snow.

3. A snowplow according to claim 1, including means for adjusting the downward extension of the stop means. 

